Sterling has rallied since the election was called, passing above 1.30 on the dollar for the first time since September 2016 in recent weeks. That has been based largely on the assumption that May's Conservative Party will win an increased majority at June's election, paving the way for her to take a more conciliatory stance on Brexit, and move away from the sort of Brexit favoured by hardline Conservative MPs, who currently have a disproportionate influence on policy thanks to the party's slim majority.

However, if her majority were to decrease, it would threaten this view.

The poll has pushed currency investors to sell sterling on Friday, with the currency losing 1.14% and dropping below the $1.28 mark. Here's how it looks as of 16.05 p.m. BST (11.05 a.m. ET):